Method for Downloading Software

1. A method for downloading software from a host device to an electronic device via a telecommunication line, the method comprising: a step of providing an electronic device which comprises: a first data storing means which stores a pre-update certificate of authenticity data in a first data storage area of said electronic device, the pre-update certificate of authenticity data certifying authenticity of pre-update software already loaded in the electronic device; and a second data storing means configured to store a second certificate of authenticity data in a second data storage area of said electronic device, the second certificate of authenticity data certifying authenticity of a second software to be newly loaded in the electronic device which will be obtained from said host device for updating the electronic device; a storing step in said second data storage area, in which, before starting a download of said second software to be newly loaded, said electronic device obtains said second certificate of authenticity data from said host device and stores said obtained second certificate of authenticity data in said second data storage area; a downloading step in which the download of said second software from said host device to said electronic device is executed; a data comparison step in which, after the download of said second software is completed, a verification of authenticity data, obtained by calculation with respect to said downloaded second software, is compared with said second certificate of authenticity data obtained in said storing step; a data storing step in said first data storage area, in which, when said second certificate of authenticity data matches said verification of authenticity data in said data comparison step, said second certificate of authenticity data is stored as the pre-update certificate of authenticity data in said first data storage area; and a run step in which, when said second certificate of authenticity data matches said verification of authenticity data in said data comparison step, said electronic device runs said downloaded second software.

2. The method for downloading software as set forth in claim 1 ; wherein, when the download of said second software is interrupted in said downloading step, said storing step in said second data storage area is skipped and the process is re-executed from said downloading step.

3. The method for downloading software as set forth in claim 1 , further comprising: a step in which, after said data storing step in said first data storage area is performed, said second certificate of authenticity data stored in said second data storage area is deleted.

4. The method for downloading software as set forth in claim 1 , further comprising: a step in which, when said second certificate of authenticity data does not match said verification of authenticity data in said data comparison step, said downloaded second software is deleted.